As in previous works
[1]}, [2]}, [3]} we find
that the model that best represents the X-ray spectra of BL Lacs is the log parabola with \(N_H\)  left free to vary. Moreover, we see that models
best fit by a log parabola show higher fluxes than those best
represented by a power law, indicating that curvature is intrinsic to
this type of object; however we are only able to evaluate curvature when spectra have
high S/N. [4]} explained the log parabolic spectrum as the
result of a statistical acceleration mechanism in which the probability of a
particle to remain inside an acceleration region decreases as the energy of
the particles increases.
